1. Field of the Invention
The invention is related to automative safety restraint systems and in particular to a low friction self-locking adjust tongue assembly for a three point seat belt system.
2. Prior Art
In vehicles equipped with active seat belt systems, self-locking adjust tongues are commonly used to snug the lap portion of the seat belt about the occupant's pelvic region. Center seats are frequently equipped with static lap belts, which after buckling, require the occupant to pull the loose end of the webbing exiting the adjust tongue to provide a snug fit about the pelvic region. The adjust tongue must be capable of preventing the loose end of the webbing from slipping in order to provide the occupant protection under crash conditions.
Government regulations require that lock-up occur when specific angles between the ingressing webbing and the base plate of the tongue are experienced, (e.g. at a minimum angle of 30.degree.). Conventional adjust tongues, such as disclosed by Stephenson in U.S. Pat. No. 4,386,452, have a lock bar slidable in slots provided in longitudinal upstanding flanges, with the webbing wrapped around the lock bar.
Continuous loop seat belt systems having retractors provided with tension eliminators are commonly used in the front outboard positions. Self-locking adjust tongues are again an essential part of such systems. The adjust tongue must be capable of sliding on the webbing to provide proper fit to the occupant but must lock up, disallowing slippage over the lock bar, under crash conditions and prevent any slack in the shoulder portion of the seat belt from being transferred to the lap portion.
Although the current self-locking adjust tongues permit the occupant to slide the self-locking adjust tongues for proper fit, the friction between the adjust tongue and the seat belt webbing is sufficient to maintain the adjust tongue in place after the tongue has been released from the buckle. Upon release of the adjust tongue, the seat belt retractor will begin to wind up the loose portion of the seat belt webbing but will stop when the adjust tongue reaches the retractor or when the retractor is located near the floor, it will stop when the adjust tongue engages web guide normally mounted to the vehicle's pillar at shoulder height. As a result, the seat belt webbing is not fully retracted into the retractor and dangles loose. Often this unretracted portion of the webbing gets caught in the door well when the vehicle's door is closed making it impossible to buckle up the seat belt without having to re-open the door to free the seat belt webbing. Further, this often results in the seat belt webbing becoming soiled and unsightly.
The invention is a self-locking adjust tongue in which the friction between the tongue and the seat belt webbing in an unbuckled state, has been reduced, such that the engagement of the adjust tongue with the retractor or web guide will not prevent the retractor from fully retracting the seat belt webbing eliminating the problem discussed above.